1. Field of the Invention
The present invention relates to a communication system to transmit content data.
2. Description of the Related Art
Recently, with the demand for reducing time and expenses for business trips, a videoconference system is becoming increasingly popular. The videoconference system is a transmission system to communicate over a communication network such as the Internet and conduct videoconferences via the communication network. In the videoconference system, the videoconference may be implemented by transmitting and receiving telecommunication data such as image data and voice data between two or more terminals at different locations.
In a case in which the two terminals at different locations start communicating and the communications are conducted via Internet Protocol (IP) telephones (i.e., one of telephone services), the Session Initiation Protocol (SIP) is generally utilized as a communication protocol for establishing a session between the two terminals. With this communication protocol (i.e., SIP), the SIP server controls a call between the terminals (i.e., a call is established between the terminals by exchanging call information between them). Once the session has been established between the terminals, they are instantly in communication and the transmission of voice data between the terminals becomes possible.
Meanwhile, in a case of OAuth 2.0 (which is the open standard for authorization according to the related art), a client receives an access token and the access token enables the client to access a protection resource. The access token is issued to the client by an authorization server, and the access token may include the authorization of an owner of the protection resource. The client uses an access token to access a protection resource provided in a resource server.
In a distributed authentication system according to the related art, a plurality of authentication servers are provided for distributing load and the distributed authentication system is adapted to identify an authentication server that has issued authentication information among the authentication servers. For example, see Japanese Laid-Open Patent Publication No. 2005-301424.
Information processing apparatuses, such as data centers in which various servers including an authorization server and an application programming interface (API) server are installed, are arranged at different locations. In each data center, an access token is issued to a terminal by the authorization server. Before requesting issue of an access token to the authorization server of the data center first, a call control is performed between the terminal and a call control server of the data center. After receiving the access token issued by the data center, the terminal may use the access token to access a protection resource of another data center. Hence, the merit of the availability of the system is maintained. In this case, the data center including the call control server to perform the call control of the terminal may be inconsistent with or different from the data center including the protection resource to be accessed by the terminal.
Here, a case in which a protection resource accessing of which is managed by a first data center is isolated from a second data center different from the first data center is considered. When a terminal accesses the protection resource of the first data center using the access token issued by the second data center, the terminal is connectable with the call control server of the second data center and the protection resource of the first data center. Hence, there is a risk that the protection resource will leak out from the call control server of the second data center.